Emerald ECU / Camel Hump Question
Emerald ECU / Camel Hump Question
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rjben

Original Poster:

917 posts

305 months

Friday 3rd September 2004
quotequote all
Joospeed,

I've just taken a look at the result of the Emerald 4.5 project (link to dyno result below)

www.emeraldm3d.com/em_projects_rose_pcurve.html

I'm assuming that the dotted line is the Emerald and the solid line is the MBE? If thats the case why does it still suffer from the camel hump? I thought this was caused by overfueling. Does it suggest an AJP8 mechanical issue as its still there with the new ECU?

Cheers,

Rob

washy

950 posts

299 months

Friday 3rd September 2004
quotequote all
I'm not Joolz But I am told this is to do with the AJP8's natural breathing. My Cerbera has a good fuel trace and ignition timing right through the rev range but it still has a huge camel hump. I'm told the only way to remove this is to de tune either side of the trough and engineer a nice flat torque curve. A process most I'm sure would agree is pointless. You can really fell the hump on my car too. It's almost like a huge turbo coming on boost. I think it gains somthing like 80lb/ft or more in 500rpm around the 4000rpm mark. Can't remember exactly with out checking the chart though. It's the nature of the beast.

Could be cured with fancy variable valve timing I suppose

J_S_G

6,177 posts

273 months

Friday 3rd September 2004
quotequote all
washy said:
Could be cured with fancy variable valve timing I suppose

You'd trust them in Blackpool to engineer that??!? Crazy talk, I say!

joospeed

4,473 posts

301 months

Friday 3rd September 2004
quotequote all
previous traces overlaid with the fuelling showed massive overfuelling in the areas of least torque .. it looked at the time (pre remap times remember) that the overfuelling was casuing the torque variation.

thinking now is that the cerbie mapping is so poor that the values used are best guess values and the changing airflow (read lowering airflow) in the low torque areas is responsible for the rich mixture, ie the mixture isn't weakened off in these areas, after all a rich mixture is safer even if it's costing torque ..

It seems to be a generic cerbie trait, however as you can see, it's possible to gain torque almost everywhere in the rev range which can only make the car go faster .. result

rjben

Original Poster:

917 posts

305 months

Monday 6th September 2004
quotequote all
Cheers Joos,

Thanks, that makes sense. Although I never realised that you get could a trough like this via an induction trait.